Is there a cleaner or direct way to copy disk images between linodes?

Looking around the new web interface under the 'Backups' I can make a current snapshot, then restore that brand new snapshot into a second linode instance. With the old interface under "settings & utilities" there is an option to clone an instance. However, Both of these options copy *all* disk images into the second linode instance.


That's a lot of un-needed copying when I just want to move one image. If the second instance was an actually installed, running, and configured I could easily do something like rsync. But my current use case is for testing my next OS upgrade with all it's install scripts. I'm trying to make sure my installs are 100% scripted. So there's nothing in the second zone.

New interface: under 'Advanced options', check the box beside one or more disk images and hit copy. You will be offered a choice of destination Linodes.

Old interface: under 'Settings and Utilities' click 'Copy individual disk images to another Linode'. You will be offered a list of images to select and a drop down menu of destination Linodes.

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/ Peter

Ah, Okay. Thanks.

I guess what tripped me up was the protection on the copy screens for running linode instances. The new interface prevents you from copying from a mounted disk image.

You should never copy a mounted image, anyway... You're likely to get a corrupt copy. If you can't afford the downtime to copy the disk, buy Backup service, create a snapshot, and restore the disk from backup to the destination VPS.

So live migration that is supported by Xen is buggy?

Moving disk images isn't live migration, just copying files (which contain your file system) from one host to another.

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/ Peter

Live migration tends to require either your storage to be on a SAN, or for you to be running network-mirrored storage.

It's not technically impossible to live-migrate the storage in a similar way to how memory is live-migrated, but it'd be tricky since the disk is so much slower than RAM. I don't think Xen implements this.

hmm... does this mean no live migration is possible at linode?

No, that's not what it means, because this has nothing to do with live migration, but yes, live migration isn't possible for other reasons.

Live migration is definitely possible with XEN, however it depends on how the hardware architecture has been designed.

Given Linodes pretty amazing uptime, i would be surprised if they didn't use live migration in some instances to take down servers for service windows etc.

They don't use an architecture that supports live migration. That's, arguably, one reason why the uptime is phenomenal.

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Good uptimes are achieved by Linode using top-quality hardware -- unlike some providers. In the event of a total (non-disk) hardware failure, the disks are moved to another server. For flaky but not completely busted hardware, you get the chance to migrate your Linode to another host at a time of your choosing (for which your 'node must be shut down), subject to a deadline -- after which the migration is done for you before the flaky gear is taken out of service.

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/ Peter